Offenses and defenses go through cyclic processes in football. Adjustments, rule changes, player styles, and coaching movement generate dominance alternation in an ever faster cycle. And that's what, almost a decade after the Legion of Boom prime, makes the start of the 2022 season a shift in defenses' favor. In the first three weeks of the regular season, the league averaged 42.1 points per game, a 5.0 points-per-game drop over the first three weeks of last season, and lower than any season since 2010.
The Legion of Boom marked a generation with single-high/cover 3 principles — much of their success was the result of having generational talents, such as Earl Thomas, Kam Chancellor, and Richard Sherman. Be that as it may, defensive coaches of that 2013 Seahawks championship team gained opportunities throughout the NFL and spread the philosophy around the league.
Defensive coordinator Dan Quinn became the Atlanta Falcons head coach. Linebackers coach Ken Norton Jr. went to the Oakland Raiders as defensive coordinator. Kris Richard, defensive backs coach and later promoted to coordinator, has had chances in Dallas and New Orleans. Defensive assistant Marquand Manuel became the Falcons secondary coach and later coordinator — he is with the New York Jets now. Even defensive quality control coach Robert Saleh grew in his career, going to the Jacksonville Jaguars as linebackers coach, to the San Francisco 49ers as a coordinator, and to the Jets as a head coach.
The popularity of this style of play had a powerful effect on offenses. After years of spreading lighter personnel, a new era of offensive football re-emerged. Coaches like Kyle Shanahan, Sean McVay, and Matt LaFleur had a system in hand ready to beat those cover 3 defenses, and that was their time to have success. As a consequence, several other assistant coaches have received chances to install their versions of the zone-blocking scheme, which wasn't as popular since the Denver Broncos won two Super Bowls running the original version under head coach Mike Shanahan.
It was time for defenses to move again.
Before the 2020 season, McVay and the Rams gave the NFL their own blueprint. The head coach decided to change coordinators, firing veteran Wade Phillips and bringing in Denver Broncos' outside linebackers coach Brandon Staley to install a version of Vic Fangio's 2-high scheme, with a significant increase in quarters coverage. Los Angeles finished that season with the best defense in football, and Staley was immediately hired to be the head coach of the other LA franchise, the Chargers.
The basic concepts
A cover 3 structure uses only one deep safety, and the two outside cornerbacks complement the outside deep zones of the field. The strong safety goes to the box, too, which allows the off-ball outside linebackers to cover flat zones and form a stronger structure to stop the run. However, modern football doesn't require such a schematic approach to defend the run. Knowing passes are much more valuable and efficient, the two-high system proposes that two safeties will play deep — when it's quarter coverage, the outside cornerbacks are responsible for the deep outside areas, too, but those are smaller areas if compared to the cover 3 structure.
The middle of the field is more susceptible, but teams avoid bigger plays and have time to make a tackle after the reception. Offenses are forced to dink and dunk — many of them are not patient enough or accurate enough to drive the entire field with small gains.
Now, there are two different front approaches in vogue. The most talked about now is the one-and-half gap, where defenses play with lighter boxes, and defensive linemen are responsible for one gap, but with attention to stop the run in another one if needed. That's what the Rams, the Chargers, and the Broncos do — and that's what the Green Bay Packers did last season, even though this year Joe Barry has run a version nearer Rod Marinelli's one-gap scheme. The San Francisco 49ers and the Cleveland Browns also run their versions with 4-3 bases, one-gap schemes, but the two-high defensive back structures are a big part of their identity.
How to attack them and results
This style of defense invites offenses to run the ball into lighter personnel. And this is exactly what these defenses want. The game has been much more relatable to old-school, pound the rock football fans.
According to TruMedia's net points, pass plays in the 2022 NFL season have been less efficient than in any of the previous decade — generating 206 points fewer than the average between 2011 and 2021. And, according to PFF, the rate of catchable balls is 63.8% in 2022, the lowest number in five years.
That inefficiency is directly proportional to the use of two-high looks. Schemes with multiple deep safeties have jumped — cover 2 zone is up to a 13.8% usage in 2022 from a four-year average of 11.2%, and quarters coverage is up to a 14.7% usage from a four-year average of 11.4%.
As a counteract, run game efficiency has increased. The efficiency is much nearer to the one of passing plays, but that generates a low-scoring effect because the clock keeps running.
It's a new era of defensive football, and it has worked so far. Now, it's the offense's turn to show how they adapt.